Expansible pulley.



ubfsszgss. Patented m 3, I900. B. B. FARNHAM.,

EXPANSIBLE PULLEY.

(Appliqation filed May 4, 1900.)

UNITED STATES BION B. FARNHAM, OF NEW YORK, N. Y.

EXPANSIBLE PU LLEY.

SPECIFICATION forming part of Letters Patent No. 652,763, dated July 3,1900.

Application filed May 4, 1900.

To all whom it may concern:

Be it known that I, BION B. FARNHAM,a citizen of the UnitedStates,residing at New York,

(Oastleton,) in the State of New York, have invented certain new anduseful Improvementsin Expansible Pulleys; and I do hereby declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains tomake and use the same, reference being had to the accompanying drawings,and to the figures of reference marked thereon, which form a part ofthis specification. I

This invention relates to expansible pulleys; and my invention is soarranged as to render the expansion and contraction thereof easy andrapid. r

In the drawings, Figure 1 shows a longitudinal sectionalviewof mypulleyin operative construction; Fig. 2, an elevation of the retaining-plate;Fig. 3, an elevation of the eX- pansion plate; Fig. 4, an elevation ofthe clamping-plate, and Fig. 5 an end view of the cap revolubly set uponone of the ends of the shafting; Fig. 6, a sectional elevation of oneside of my pulley,en1arged to clearly show the parts. 7

The numeral 1 indicates a tubular shaft having openings 2 through itswalls in order that the parts occupying the interior may be seen andeasily arranged and repaired. In the shaft 1 I preferably set circularblocks 3, with openings in them and arranged to act as boxes to supportand in which the rods 6 and 7 may rotate. While I prefer this method ofmaking the rods 6 and 7 rotatable, I do not confine myself thereto, asany other method may be used that may be desired. The rods 6 and 7 areprevented from having an endwise thrust preferably by means of washers17, but any other means may be used. The rods 6 and 7 are each threadedright and left 'i. 6., that portion of rod 6 restingin the tubular shaftto the left of the central block is threaded left hand, as at 6, andthat portion thereof resting in the shaft to the right of said block isthreaded right hand, as at 6, while that portion of rod 7 resting in theshaft to the left of the central block is threaded right hand, as at 7,while that portion resting in the shaft to the left of said block isthreaded left hand, as at 7.

each of said nuts. which pass through the openings 2 in shaft 1,

Serial No. 15,481. (No model.)

Rod 6 will be seen to pass througha nut 11, the rod-threading meshingwith appropriate threading in These nuts have shanks precisely as dothose shown at 11 on rod 6. ,On the left-hand end of the shaft 1 isrevolublyset a cap 4, with an opening in its outer end and having thecircular edge of the opening toothed, as seen at 5 in Fig. 5. Through oneach rod is set a small gear 8 and 9, ar-

Yranged to be moved lengthwise on theshafts,

so as to be thrown in and out of gear when desired, and to prevent theirbeing revoluble v on the rods they are fitted to slide over a feather10, which is shown onlyon rod 6, that on rod 7 being on the rear side ofthe rod. Both these small gear mesh with teeth 5 on the revoluble cap4when they mesh with each other; but when either of them is slid outwardon its respective rod, as is gear 8 on rod '6, then but one of them(gear 9) meshes with teeth 5. This is arranged so that when it isdesirable to move clamping-plate l2 independent of the spreading-plate13 it may be done, which allows of making plate 12 fully and completelyclamp arms 15 in secure position. Clamping-plate 12 has slots 12 and isfixed upon the shaftl to slide laterally thereon, but not to rotate onthe shaft. Spreading-plate 13 is likewise fixed upon the shaft 1 and ispreferably a solid plate having a beveled edge. Retaining-plates 14 areimmovably affixed to the shaft and have slots 13, and betweenretaining-pl ates 14 rests the segmental pulley-block 16, each of thesegments thereof having a downwardly-sloping arm 15, which passesthrough one ofthe slots 513?, rests on the beveled edge ofspreading-plate 13, and passes through one of the slots 'l2 in clampingplate 12.

The operation is as follows: Gear 8 being slid along the rod 6 until itmeshes with teeth 5 on cap 4 and with the gear 9 and the cap 4 beingturned or rotated in one direction this opening both of the rodsprotrude, and

clamping-plates 12 and spreading-plates 13 will move outward fromretaining-plates 14, and as arms 15 slide over or upon the beveled edgeof spreading-plates 13 segments 16 will be compelled to rise betweenplates 14 and increase the diameter of the segmental pulley. \Vhen cap 4is turned oppositely, clamping-plates 12 and spreading-plates 13 willapproach retaining-plates 14 and the segments l6 will fall betweenplates 14 and decrease the diameter of the pulley. When it is desired tooperate clamping-plate 12 alone, gear 8 is left to mesh with teeth 5 oncap 4, while gear 9 is thrown out of mesh by sliding it along the rod 7,and by reversing the positions of the gears S and 9 the spreading-plate13 may be moved without moving plate 12. It will be evident to thoseskilled in the art that plate 12 may be moved in other ways and by othermeans than I have shown, and I show the way seen in the drawings only asmy preferred method, while I do not confine myself thereto.

lVhile I have not shown any particular manner of rotating cap 4 exceptby handpower, it may be made to rotate by means of a belt passed aroundcap 4 or by gearing it to a power-operated shaft or otherwise, as thecircumstances may demand. By forming sprockets on its periphery andpassing a suitable chain over it, so as to operate with said sprockets,the chain forming a chain belt,

the cap 4 may be operated by drawing on the chain. I have used thismethod in some cases and find it to operate well. By use of clampingplate 12 with its inwardly projecting and angular flange I am enabled todo away with all set-screws and gibs, such as were shown and describedin my patent dated July 10, 1894, and numbered 522,658, and I am enabledto make a much better and secure clamp upon the arms 15, and by use ofthe two threaded rods 6 and 7 inside the tubular shaft and arrangedpractically as shown I am enabled to better and easier operate thespreading and clamping plates, and therein said shaft, the spreading andclamping plates I arranged to be thrust lengthwise on said shaft, and aplurality of threaded rods inside said shaft, the threading beingarranged to move nuts outwardly and inwardly on said shaft in unison,said nuts being fixed respectively to the clamping-plates and to thespreading-plates, the rods having means whereby they may be revolvedirrespective of the revolutions of the shaft substantially as described.

2. In a segmental expansible pulley having projecting arms connected tothe segments, a tubular shaft, and spreading-plates, clamping plates andretaining plates arranged upon the shaft, the spreading and the clampingplates being arranged to have lateral thrust along the shaft, and aplurality of threaded rods in said tubular shaft and nuts on said rods,some of said nuts being afiixed to the spreading-plates and theirthreads meshing with the threads on one of the rods, and other of saidnuts being affixed to the clamping-plates and their threads meshing withthose on the other rod in order that the said spreading and the clampingplates may be moved laterally along said tubular shaft and clamp thearms of the segments, and means whereby the threaded rods may be rotatedseparately or collectively, all combined substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

BION l3. FARNHAM.

Witnesses:

W. J. Honor-r, W. M. BROWN.

